2-isopropyl-5-methyl-2-hexenal, 2-isop-ropyl-5-methylhexanal,3-hydroxy-2-isopropyl-5-methylhexanal, and derivatives thereof as tobacco flavorants

ABSTRACT

The base-catalyzed self-condensation of isovaleraldehyde yields a mixture of threo- and erythro-2-isopropyl-5-methyl-3hydroxyhexanal. The reaction conditions can be so chosen as to favor predominance of one isomer over the other. Upon vacuum distillation of the mixture, one of the isomers preferentially dehydrates yielding 2-isopropyl-5-methyl-2-hexenal as a distillate and unchanged 3-hydroxy-2-isopropyl-5-methylhexanal as the residue. These aldehydes are the parent members of a class of compounds composed of 2-isopropyl-5-methylhexanal, 3-hydroxy-2isopropyl-5-methylhexanal, 2-isopropyl-5-methyl-2-hexenal, and the alcohol and carboxylic acid derivatives of these aldehydes, the ester and ether derivatives of the alcohols and acids, as well as certain other alcohol and ketone derivatives. These compounds are useful as tobacco additives to modify the taste of the tobacco, and/or as intermediates for the preparation of tobacco additives.

D United States Patet 1151 3,704,714

Kallianos et al. 1 Dec. 5, 1972 s41 2-ISOPROPYL-5-METHYL-2-HEXENAL, 3,111,127 11/1968 .larboe ..131/17 2-ISOP-ROPYL-5-METHYLHEXANAL,3- 3,174,485 3/1965 Griffith etal ..131/17 HYDROXY-2-ISOPROPYL-5- 3,381,691 5/1968 Schumacher et a1. ..131/144 X METHYLHEXANAL AND 3,449,407 6/1969 Theimer et al. ..131/17 X DERIVATIVES THEREOF AS Prllfltlr) Examlr lerAldrich F. Medbery Assistant Examiner-George M. Yahwak [72] Inventors: Andrew G. Kalhanos; Albert H. Atmmey ](eny(m & Kenyon Reilly Carr & Chapin 1 Warfield; Melvyn I. Simpson, all of Durham, N.C. [57] ABSTRACT Assigneel Llggett & Myers Incorporated, New The base-catalyzed self-condensation of isovaleral- York dehyde yields a mixture of threoand erythro-2- 22 Filed; June 16, 7 isopropyl-S-methyl-3-hydroxyhexanal. The reaction conditions can be so chosen as to favor predominance [21] Appl' 153,900 of one isomer over the other. Upon vacuum distilla- R l t d tion of the mixture, one of the isomers preferentially e a e U S Application Data dehydrates yielding 2-isopropyl-5-methyl-2-hexenal as Con i nmp r f r N 2, March 12, a distillate and unchanged 3-hydroxy-2-isopropyl-5- 1969 abandoned and 57,4141 June methylhexanal as the residue. These aldehydes are the i z z and 73,194 Sept" parent members of a class of compounds composed of l an one 2-isopropyl-S-methylhexanal, 3-hydroxy-2-isopropyl- S-methylhexanal, 2-isopropyl-5-methyl-2-hexenal, and [52] US. Cl ..131/17 R, 99/140,131/144 the alcohol and carboxylic acid derivatives ofthese ab [51] Int. Cl. ..A24b 15/00 [58] Field is h 131/17 140 99/140 dehydes, the ester and ether der1vat1ves of the al- 0 earc cohols and acids, as well as certain other alcohol and [56] References Cited ketone derivatives. These compounds are useful as tobacco additives to modify the taste of the tobacco, UNITED STATES PATENTS ass/or as intermediates for the preparation of tobacco t 2,995,476 8/1961 Hind et al ..l3l/l7 a l Wes 3,047,433 7/1962 Bauley et al ..l3l/l7 8 Claims, N0 Drawings DISCLOSURE OF THE INVENTION This application is a continuation in-part of each of Ser. No. 806,682 filed Mar. 12, I969, Ser. No. 57,414

filed June 19, 1970, and Ser. No. 73,194 filed Sept. l7, 10

1970, all now abandoned.

This invention relates to novel aldehydes, alcohols, acids, ethers and esters as tobacco flavorants. More particularly, this invention is concerned with 3-hydroxy-2-isopropyl-5-methylhexanal, 2-isopropyl-5-methyl-2 -hexenal and 2-isopropyl-5-methylhexanal, the corresponding primary alcohols and their ethers and esters, the corresponding carboxylic acid derivatives and esters of the acids, 3-iso-propyl-6-methylheptan-2- ol, 3-isopropyl--methylheptan-Z-one and their corresponding unsaturated derivatives as tobacco additives to modify the flavor of the tobacco smoke.

The compounds to which this invention relates may be represented by the formula:

wherein Y is hydrogen, hydroxyl, lower acyloxy, or lower alkoxy; X is hydroxymethyl, lower acyloxymethyl, lower alkoxymethyl, 2-hydroxyethyl, formyl, acetyl, carboxyl or lower alkoxycarbonyl and y is or I. These compounds may be further classified as follows:

3-Hydroxyhexanal derivatives:

0 Z (CHa)2CHCH2('JH-CHX a)2 (IA) 2-hexenal derivatives:

(CH1)zCHCH;CH=C-X a)2 (IB) Hexanal derivatives:

(CHa)2CHCH2CH2CHX wherein X is as defined above and Z is hydrogen, acyl or alkyl. Of these compounds, all but the hexen-l-ol esters and ethers within the scope of formula 1B are useful as tobacco flavorants, and the unsaturated esters and ethers are useful as intermediates for the corresponding saturated esters and ethers of formula IC. By the term lower alkoxy" is meant an alkoxy group of from one to three carbons, i.e., methoxy, ethoxy, propoxy and isopropoxy. Methoxy is particularly preferred. By the term lower acyloxy is meant an acyloxy group of from two to four carbons, i.e., acetoxy, propionoxy or butyroxy with acetoxy being preferred.

It will be apparent from a consideration of the structural formulas that for compounds represented by formula IB certain geometrical isomers are possible, and for those represented by formula IA certain diastereoisomers are possible. These isomers are ineluded within the scope of this invention since they all impart desirable flavor properties.

These products are readily obtained by a series of reactions beginning with isovaleraldehyde which, in the first step of the synthesis, is self-condensed in the presence of a base to yield a mixture of the threoand erythro-isomers of 3-hydroxy-2-isopropyl-5-methylhexanal. The condensation is conducted in an aqueous reaction medium having dissolved therein a strong base, such as an alkali metal hydroxide, e.g., potassium hydroxide. The reaction is usually effected at room temperature or below, i.e., temperatures at or below about 25C. In a preferred technique, a solution of isovaleraldehyde in an organic solvent is admixed with aqueous base at reduced temperatures, preferably 0 to 5C., and then the reaction mixture vis maintained at room temperature for about 6 to about 120 hours or more, depending upon the desired product, with dehydration being favored by longer reaction times.

With a reaction time of about 6 hours 3-hydroxy-2- iso-propyl-S-methylhexanal isomer A is isolated and solidifies when placed in the refrigerator, m.p. 4749 Prolonged reaction time favors the production of 2- isopropyl-S-methyl-2-hexenal and 3-hydroxy-2- isopropyl-S-methylhexanal isomer B. This mixture can be separated by distillation at about 24 mm Hg, the former distilling at l00, the latter at l20-l 30.

The 3-hydroxy-2-isopropyl-5-methylhexanal and the 2-isopropyl-5-methyl-2-hexenal are readily oxidized to the corresponding acids by conventional oxidation techniques, as by bubbling air or oxygen through the aldehyde at room temperature or treatment with oxidizmg agents. 7

The resulting acids are then esterified in known manner, as by acid-catalyzed reaction with a low molecular weight alcohol of the formula ROI-l, wherein R is lower alkyl. A preferred method comprises the use of perchloric acid or sulfuric acid and methanol. Alternatively, the methyl ester is obtained by reaction of the acid with diazomethane.

The 3-hydroxy-2-isopropyl-S-methylhexanal and the 2-isopropyl-5-methyl-2-hexenal are also readily reduced, as by treatment with sodium borohydride in conventional manner, to the corresponding primary alcohol, i.e., 2isopropyl-5-methylhexane-l,3-diol and 2- isopropyl-S-methyl-2-hexen-l-ol. Alternatively, the hexenal compound can be hydrogenated under mild conditions, e.g., over a palladium catalyst, to yield 2- isopropyl-S-methyl-hexanal, or under more severe con- I ditions, e.g., over platinum oxide and ferrous chloride,

to yield 2-isopropyl-5-methylhexanol, which may be esterified or etherified in known manner.

The saturated hexanal may be oxidized to the corresponding acid as describe above, and the acid converted to a lower alkyl ester.

All of the alcohols may be fully or, in the case of the derivatives of Formula IA, partially esterified or etherified in known manner.

As noted above, most of these products are useful as additives to tobacco, especially cigarette tobacco, to modify the flavor of the tobacco. The amount of the compound which is added to the tobacco will vary with the compound and the effect desired. In general, however, amounts of at least about 0.02 milligrams per gram of tobacco are employed. Normally amounts exceeding 0.5 mg per gram of tobacco are undesirable because of harshness. When employed in filter cigarettes higher amounts are required to achieve the same effect obtained with non-filter cigarettes.

The following examples are illustrative:

EXAMPLE 1 To a cooled (C. solution of isovaleraldehyde 100 g.) in 100 ml. of ether was added with stirring 200 ml. of aqueous 15 percent potassium hydroxide solution over a period of 45 minutes and at such a rate that the'temperature did not rise above 5C. After cooling at 0C. for an additional minutes, the cooling bath was removed and the mixture was stirred for 24 hours. The liquid layers were separated; the aqueous layer was washed with ether and the combined ether solutions were washed successively with 2 N acetic acid, saturated sodium bicarbonate solution, water and saturated sodium chloride solution. After drying over anhydrous magnesium sulfate, the ether was removed on arotary evaporator and the product was distilled under vacuum on a Vigreaux column. The 2-isopropyl-5-methyl-2- hexenal distilled at 95100/24 mm Hg. Gas-liquid chromatography of the latter results in a peak consisting of isovaleraldehyde due to thermal retroaldol decomposition in the hot (200C.) column inlet.

EXAMPLE 11 The unsaturated aldehyde recovered in Example 1 was purified further by fractionation using a semimicro spinning-band column and a manostat to regulate the pressure at 200 mm. Four fractions were collected between 135 and 136l200 mm. Hg. The infrared (IR) and mass spectra of the combined fractions were consistent with the assigned structure; i.e., 2970 I and 2880 (CH 2710 (CHO), 1690 (conjugated aldehyde carbonyl), 1630 (C=C), 1470 (CH, C11,), 1423 (CH bending), 1388 and 1370 (isopropyl), 1281 (C=C-C=O) and 1143 cm" (isopropyl); the mass spectrum gave the molecular ion at m/e 154, and peaks corresponding to loss of 15, 43 and 57 units, in addition to those at m/e 29 and 15. The 2,4- dinitrophenylhydrazone was prepared and recrystallized from methanol, orange-red crystals, m.p. 129-13 2C., and showed one spot on thin layer chromatography using several solvent systems. Analysis. Calcd. f0! CmHggN 4041C, H, N, Found: C, 57.44; H, 6.67; N, 16.68.

EXAMPLE Ill The aldol of Example 1 was converted to 3-hydroxy- 2-isopropy1-5-methy1hexanoic acid by allowing the higher-boiling fraction of Example 1, 3-hydroxy-2- isopropyl-5-methylhexanal, to stand for several weeks, or by bubbling air through the viscous liquid for several days, whereupon crystals of the acid separated. Recrystallization from cold methylene chloride-carbon tetrachloride gave white needles, mp. 88-89. The mass spectrum gave the molecular ion at m/e 188, with major peaks at 170, 131, 113, 102, 87, 85, 71, 69, 43, 41, 29, 27. The m/e 170 and 102 peaks arise by loss of water and by reverse aldol reaction, respectively; the others are straightforward fragmentation peaks. The IR spectrum (CH Cl shows acid and hydroxyl OH bands at 3300-3000 and 3600-3500 cm, and has three carbonyl bands, for dimer (1700 cm), intramolecularly hydrogen-bonded form (1726 cm"), and nonbonded form (1752 cm"). By the use of dioxane as a solvent the band at 1700 cm'l reverts to the bonded form 1726 cm'l thus indicating that the hydroxyl on carbon 3 is hydrogen-bonded to the carbonyl oxygen. Analysis.-Calcd. for Cid-1 0 C, 63.80; H, 10.71. Found: C, 64.06; H, 10.55.

EXAMPLE 1V Methyl 3-hydroxy-2-isopropyl-5-methylhexanoate was prepared from the acid of Example 111 using excess ethereal diazomethane. Quantitative conversion was indicated by thin layer chromatography (Silica gel G, benzene-ethyl acetate, 9:1). The compound was chromatographed on grade [11 neutral alumina (-200 mesh), using benzene as the eluent. An analytical sample was obtained by gas liquid chromatography on a 10 ft. X '16 in stainless steel column packed with 10 percent GE-SF-96 on Gas Chrom RZ, 100-200 mesh, flow rate 40 ml. Helmim; column temp. 68 initial hold/4 min, program 4lmin. thereafter. The retention time under these conditions was 30 minutes. IR spectrum: 3540 cm(bonded 01-1), 1716 cm" (bonded ester C=0). NMR spectrum: singlet, 3.66 ppm OCl-l broad singlet, 2.35 ppm. bonded OH, overlapping doublet, 1.00 ppm (J 6.0 cps), and 0.88 ppm (J 5.5 cps), isopropyl methyls. The mass spectrum gave a very small molecular ion (m/e 202) peak, and peaks at m/e 184 (loss of H 0), 171 (loss of OCH (base, MC H (OH-rearrangement), 1 13 (B-cleavage, loss of H and 101 (loss of CH from 116). Analysis. Calcd. for C H O? C, 65.31; H, 10.96. Found: C, 65.14; H,

A 70-80 percent yield of the ester was also obtained by treatment of the acid of Example 111 with perchloric acid in methanol; i.e., l g. of acid, 25 ml. methanol and 0.1 ml. 70 percent perchloric acid was refluxed on the steam bath overnight. The methanol was evaporated and the residue taken up in ether. The ether solution was washed with dilute sodium bicarbonate solution, water and saturated sodium chloride solution, dried over anhydrous sodium sulfate and evaporated. The IR spectrum was identical to that of the ester prepared using diazomethane.

EXAMPLE V 2-Isopropyl-5-methyl-2-hexanoic acid was prepared from the unsaturated aldehyde of Example 1 as follows: A solution of 3.5 g. of 2-isopropyl-5-methyl-2-hexenal in 400 ml. of acetone was cooled to l015C. and stirred while bubbling nitrogen through the mixture, and 4-5 ml. of Jones reagent was added dropwise until the orange color just persisted. The cooling bath was removed during this time. The solution was filtered; 50 ml. of water was used to wash the flask and added through the filter to the solution. The acetone was evaporated in vacuo and the mixture extracted with ether. The ether solution was extracted with 15 percent potassium hydroxide solution, and the basic extract was acidified with 10 percent sulfuric acid, followed by a final ether extraction. The ether solution was dried over anhydrous sodium sulfate an purified by preparative gas liquid chromatography on a 10 ft. X 96 in. copper column packed with 17 percent Carbowax 20M on Chromosorb P, 60-80 mesh, flow rate 70 ml. Pie/min; column temp. 240. Under these conditions the clear liquid had a retention time of 18 minutes. The

IR spectrum (CCl gave broad acid OH absorption at 3000-2500 cm, and C=C stretching at 1678 cm, indicating conjugation with a carbonyl group. The mass spectrum showed the molecular ion peak at m/e 170, and large peaks at m/e 43 (base), 56 (90 percent), 69, 83, 113,115,128 and 155. The NMR spectrum (CCl gave a 6H doublet (J 6.3 Hz) at 0.97 ppm and another 6-H doublet (J 7.1 Hz) at 1.20 ppm (isopropyl methyls); a 2-H triplet" (J ca. 7 Hz) at 1.20 ppm (overlapping doublets due to methylene at C4), a l-H septet (J ca. 7 Hz) at 2.90 ppm (methine of 2-isopr0pyl), a l-H triplet (J 7.6 Hz) at 6.76 ppm (vinylic proton at C-3), and a l-H singlet at 11.95 ppm (acid OH).

EXAMPLE Vl Methyl 2-isopropyl-5-methyl-2-hexenate was prepared from the acid of Example V using diazomethane in a manner identical to that of Example IV. The ester was also prepared as follows: 33 g. of crude 2-isopropyl-5-methyl-2-hexenoic acid was dissolved in 300 ml. of dry methanol containing 3, ml. concentrated sulfuric acid, and the mixture refluxed for 24 hours. Solid sodium bicarbonate was used to neutralize the solution, and 200 ml water added. The methanol was evaporated in vacuo, and the whole extracted 4 times with ether. The ether extracts were combined, washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. The ester (18 g.) was distilled through a semi-micro distillation apparatus which included a foam-trap and Claisen-head. The material distilling at 534/l.5 mm Hg weighted 13 g. The forerun and pot-residue also consisted largely of the ester. The IR spectrum (CCl showed bands at 1713 (ester C=O, conjugated), 1634 (C=C, conjugated), 1390l370 (isopropyl doublet), 1280, 1221 and l 152 cm. The NMR spectrum (CCl showed two 6-H doublets (0.96 ppm, J 6.4 Hz, and 1.17 ppm, J =7.0 Hz) for the two isopropyl groups, a 2H pair of overlapped doublets centered at 2.08 ppm (J =ca. 6-7 Hz) for the C4methylene group, the O-methyl singlet at 3.67 ppm, and the vinyl triplet l-H) (6.5 ppm, J 7.5 Hz). The mass spectrum gave peaks at m/e 184 (molecular ion), 169, 153, 142, 141, 137, 128, 127, 110, 109, 95, 83, 81, 75, 69, 67, 59, 56, 55, 53, 43 (base peak) and 41.

EXAMPLE VII Aliquots of 10 11.1 of a solution of 0.5 mg of 2- isopropyl-5-methyl-2-hexenal in 1 ml 95 percent ethanol were injected uniformly along a path of 55 mm length in experimental cigarettes manufactured from a commercial blend of tobaccos. The sample cigarettes were equilibrated at 60 percent relative humidity for lO-l 2 hrs. before smoking.

The smoke characteristics of samples of the cigarettes were evaluated by an experienced taste panel. Each sample of cigarettes was compared to a corresponding control handled in the same manner as the test sample, but not containing the active flavor ingredient.

Cigarettes containing 2-isopropyl-5-methyl-2-hexenal produced on smoking a low to moderate suggestion of a Turkish tobacco-type flavor and a saltymetallic sour taste complex related to some Turkish types.

EXAMPLE vur A solution of 10 mg of 2-isopropyl-5-methyl-2-hexenal in 4 ml of percent ethanol was applied by spraying to 200 gm of a cased and cut commercial blend of tobaccos, and the treated tobacco was made into cigarettes (Sample A). In a similar manner, cigarettes were made employing solutions of 20, 30 50 mg of 2- isopropyl-S-methyl-2-hexenal in 4 ml of 95 percent ethanol (Samples B, C and D, respectively).

The cigarettes of Sample -A and B exhibited a complex and interesting aroma which had notes of sour, dried fruit, honey and licorice. The smoke from these cigarettes produced a dominant bitter-woody taste'and, especially those of Sample B, produced some throat irritation. The cigarettes of Samples C and D exhibited unpleasant astringency and irritation on smoking.

EXAMPLE IX A solution of 25 mg of 2-isopropyl-5-methyl-2-hexenal in 4 ml of 95 percent ethanol was applied by spraying to 200 gm of a cased and cut commercial blend of tobaccos. The thus treated tobacco was made into cigarettes and cellulose acetate filters were attached. A second sample was prepared in a similar manner, except that three-piece filters consisting of cellulose acetate-charcoal-cellulose acetate were attached instead of the cellulose acetate filter. Cigarettes having attached cellulose acetate filters showed slightly enhanced tobacco fragrance and more fullness, whereas cigarettes having attached three-piece cellulose acetate and charcoal filters gave no improvement over the control on smoking.

EXAMPLE X A solution of 20 mg of 2-isopropyl-5-methyl-3- hydroxyhexanoic acid in 4 ml of 95 percent ethanol was applied by spraying to 200 gm of a cased and cut commercial blend of tobaccos, and the thus-treated tobacco was made into cigarettes. The cigarettes produced more amplitude, more blended tobacco fragrance, and more sweet taste than the control when smoked. in addition a alight pepperiness was observed.

EXAMPLE Xl A solution of 10 mg methyl 2-isopropyl-5-methyl-3- hydroxyhexanoate in 4 ml of 95 percent ethanol was applied by spraying to 200 gm of a cased and cut commercial blend of tobaccos. The thus-treated tobacco was made into cigarettes (Sample A). In a similar manner samples were produced employing solutions of 20, 30 and 50 mg. of methyl 2-isopropyl-5-methyl-3- hydroxyhexanoate in 4 ml of 95 percent ethanol (Samples B, C and D, respectively).

The cigarettes of Sample A were not significantly different from the control, but those of Samples B produced a more balanced flavor spectrum than the control when smoked, with a higher level of sweet taste, less bitter taste, less drying and a low-level woody character. The cigarettes also produced a smoother, smoke, and a modest taste improvement over the control. The cigarettes of Sample C and D produced a bitter, pipe-stem taste and a high level of pepperiness and sting.

EXAMPLE x11 A solution of 20 mg of 2-isopropyl-5-methyl-2-hexenoic acid in 4 ml of 95 percent ethanol was applied by spraying to 200 gm of a cased and cut commercial blend of tobaccos. and the thus-treated tobacco was made into cigarettes.

Cigarettes prepared in this manner exhibited increased fullness and interest in the smoke, but there were no flavor or taste differences from the untreated control.

EXAMPLE XIII EXAMPLE XIV A solution of mg of 2-isopropyl-5methyl-2-hexenal and 20 mg of methyl 2-isopropyl-5-methyl-3- hydroxyhexanoate in 4 ml of 95 percent ethanol was sprayed onto 200 gm of a cased and cut commercial blend of tobaccos and the blend was made into cigarettes. The cigarettes exhibited enhanced tobacco fragrance which was described as having cocoa-burley character. There was also a more complex flavor spectrum characterized by a woody-Turkish note.

EXAMPLE XV 2-lsopropyl-5-methyl-2-hexen-l-ol was prepared by reduction of the corresponding aldehyde with sodium borohydride in ethanol. After appropriate work-up, the product was obtained by distillation at 6l6 2C/ 1-2 Aliquots of 10 ,ul of a solution of 20 mg 2-isopropyl- 5-methyl-2-hexen-l-ol in 2 ml of 95 percent ethanol were injected uniformly along a path of 55 mm length in experimental cigarettes manufactured from a commercial blend of tobaccos. The solvent was removed from each cigarette by a gentle stream of air.

Upon organoleptic evaluation the cigarettes contain ing the 2-isopropyl-5-methyl-2-hexen-l-ol exhibited moderate burnt, green, and sweet notes, while drying and coating were low to moderate as were mouth and throat irritations. Bright tobacco-like notes in the aftertaste were intensified.

EXAMPLE XVI Hydrogenation of 2 g. 2-isopropyl-5-methyl-2-hexenal over 0.1 g. platinum oxide and 0.005 g, ferrous chloride in ml. methanol at room temperature and 30-40 pounds pressure produced 2-isopropyl-5+ methylhexanol. The product was purified by molecular consistent with the assigned structure.

Aliquots of 10 71.1 of solution of 2-isopropyl-5 -methylhexanol were injected uniformly along a path of 55 mm length in experimental cigarettes manufactured from a commercial blend of tobaccos. The cigarettes were submitted to a flavor panel for organoleptic evaluation. It was found that 25 ppm, a very desirable wetting effect of low intensity is imparted to the smoke of the treated cigarettes along with a slight increase in sour character. At levels of 50 to 200 ppm, the compound contributes undesirable increases in pepperiness, oiliness, green and sour character.

EXAMPLE XVII 2-Isopropyl-5-methylhexyl acetate was synthesized by hydrogenation of lavandulyl acetate in methanol over 5 percent palladium on carbon at room temp. and 30-40 pounds pressure. The product was purified by distillation at 111-115/25-30 mm; r3 3 5.75 (C=O); 7.19, 7.29 (isopropyl); 8.1 p. (C 0); mass spectrum: M at m/e 200.

Aliquots of 10 pl of solutions of Z-isopropyl-S- methylhexyl acetate were injected uniformly along a path of 55 mm length in experimental cigarettes manufactured from a commercial blend of tobaccos. The cigarettes were submitted to a flavor panel for organoleptic evaluation. A highly desirable salivating effect is produced at 25 ppm. It was found that at higher levels, a citrus-like character is imparted to the smoke flavor along with burn and peppery notes.

EXAMPLE XVIII EXAMPLE XIX 2-Isopropyl-5-methyl-2-hexen-l-ol was converted to the corresponding methyl ether by treatment with sodium followed by methyl iodide in anhydrous ether; ,ggg 5.90 c=c 7.21, 7.30 (isopropyl); 9.08 a (c 0); mass spectrum molecular ion at m/e U0. The

NMR spectrum was consistent with the assigned structure. This product can be hydrogenated in known manner to yield 2-isopropyl-5-methylhexyl methyl ether.

EXAMPLE XX 3-Isopropyl-6-methyl-2-heptanol was prepared from 2-isopropyl-5-methylhexanai by treating 5 g. of the aldehyde with 24 ml. of 1.66 M methyl lithium in 25 ml. anhydrous ether at l0l5C under an atmosphere of nitrogen. After addition of the methyl lithium was complete, the solution was stirred under reflux for 1 hour, cooled to 0C, and hydrolyzed with 15 ml. of icecold 15 percent sulfuric acid. The layers were separated and the organic layer was washed with saturated sodium bicarbonate solution, water, and saturated sodium chloride solution. dried over anhydrous sodium sulfate. and the solvent removed on the rotary evaporator. The product was purified by molecular distillation at lC/20-25 MM; 5." 2.75 (on); 7.20 and 7.30 (isopropyl): 9.17 t (C-O): mass spectrum: molecular ion at m/e 172.

Aliquots of Al of a solution of 10 mg. 3-isopropyl- 6-methyl-2heptanol in 1 ml. of 95 percent ethanol were injected uniformly along a path of 55 mm. length in experimental cigarettes manufactured from a commercial blend of tobaccos. The solvent was removed from each cigarette by a gentle stream of air. Upon organoleptic evaluation. the treated cigarettes were judged to produce a smoke characteristic of burley tobacco with subdued robustness and sweet character.

EXAMPLE XXl 3-Isopropyl-6-methyl-2-heptanone was prepared by reacting 2-isopropyl-5-methylhexanoic acid with ethyl lithium as follows: A solution of 2 g. of the acid in 25 ml. anhydrous ether was treated with 16 ml. of 3.5 M methyl lithium in ethyl ether at 10C under a nitrogen atmosphere. The reaction solution was then refluxed with stirring for 2 hours, cooled to 0C, and hydrolyzed with 10 ml. of percent sulfuric acid. The layers were separated and the organic layer was washed sequentially with saturated sodium bicarbonate solution, water, and saturated sodium chloride solution, dried over sodium sulfate, and evaporated on the rotary evaporator. The product was purified by molecular distillation at 70-s0c/20-25 mm; .55; 5.85 (c=o); 7.21 and 7.30 [-L (isopropyl); mass spectrum: molecular ion at m/e 170.

Aliquots of 10 p.l of a solution of 10 mg. 3-isopropyl- 6-methyl-2-heptanone inl ml. 95 percent ethanol were injected uniformly along a path of 55 mm. length in experimental cigarettes manufactured from a commercial blend of tobaccos. The solvent was removed from each cigarette by a gentle stream of air. The treated cigarettes were evaluated organoleptically and were judged to produce a smoke having a sharp green note with a slight increase in sour character.

The additives of this invention may be applied to the tobacco by spraying, dipping or otherwise, utilizing suitable suspensions or solutions of the additive.

in addition to being useful in the manufacture of cigarette tobacco, the additives are also suitable for use in connection with the manufacture of pipe tobacco or other tobacco products.

It will be appreciated that while several embodiments of this invention are shown above, the invention is not to be limited thereto, since many modifications will be obvious to those skilled in the art and hat the present invention is defined by the appended claims.

What is claimed is:

l. A tobacco composition including in an amount sufficient to modify the organoleptic characteristics of the tobacco at least one compound of the formula:

wherein Y is hydrogen, hydroxyl, lower alkoxy or lower acyloxy; X is hydroxymethyl, lower alkoxymethyl, lower acyloxymethyl, 2-hydroxyethyl, formyl, acetyl, carboxyl or lower alkoxycarbonyl; and y is 0 or 1, with the proviso that X is acyloxymethyl or alkoxymethyl only when y is l.

2. A composition according to claim 1 wherein y is 1 and Y is hydroxyl.

3. A composition according to claim 2 wherein X is a radical selected from the group consisting of hydroxymethyl, formyl, carboxyl and methoxycarbonyl.

4. A composition according to claim 1 wherein y is 0.

5. A composition according to claim 4 wherein X is a radical selected from the group consisting of hydroxymethyl, formyl, carboxyl and methoxycarbonyl.

6. A composition according to claim 1 wherein y is l and Y is hydrogen.

7. A composition according to claim 6 wherein X is a radical selected from the group consisting of hydroxymethyl, methoxymethyl, acetoxymethyl, formyl, carboxyl, 2-hydroxyethyl and acetyl.

8. A tobacco smoking article including a tobacco composition according to claim 1.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,TOQjTlQ Dated December 5, 97

(Serial N 53,9 (Filed June 16, 1971) Inventor(s) Andrew G; Kallianos et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 31, before "(OH-rearrangement) delete minus sign and insert --ll6--.

Column t, line 33, in the. Analysis, correct formula to read as follows C H O Column 7, line 23, correct spelling of -than-.

Column 10, line 9, correct spelling of --that--.

Signed and sealed this 1st day of May 1973.

(sEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSGHALK Attesting Officer Commissioner of Patents ORM PO-IOSO (10-69) USCOMM-DC 60376-P69 Q u.s. GOVERNMENT PRINTING OFFICE: I969 0-366-334 

2. A composition according to claim 1 wherein y is 1 and Y is hydroxyl.
 3. A composition according to claim 2 wherein X is a radical selected from the group consisting of hydroxymethyl, formyl, carboxyl and methoxycarbonyl.
 4. A composition according to claim 1 wherein y is
 0. 5. A composition according to claim 4 wherein X is a radical selected from the group consisting of hydroxymethyl, formyl, carboxyl and methoxycarbonyl.
 6. A composition according to claim 1 wherein y is 1 and Y is hydrogen.
 7. A composition according to claim 6 wherein X is a radical selected from the group consisting of hydroxymethyl, methoxymethyl, acetoxymethyl, formyl, carboxyl, 2-hydroxyethyl and acetyl.
 8. A tobacco smoking article including a tobacco composition according to claim
 1. 